#!/usr/bin/env node

/**
 * Module dependencies.
 */
const http = require('http');
const debug = require('debug')('learning_api:server');
const app = require('./app');

/**
 * Get port from environment and store in Express.
 */
const port = normalizePort(process.env.PORT || '3000');
const env = process.env.NODE_ENV || 'development';

/**
 * Create HTTP server.
 */
const server = http.createServer(app.callback());

/**
 * Listen on provided port, on all network interfaces.
 */
 server.listen(port);
 server.on("error", onError);
 server.on('listening', onListening);

/**
 * Normalize a port into a number, string, or false.
 */
function normalizePort(val) {
  const port = parseInt(val, 10);

  if (isNaN(port)) {
    return val;
  }
  
  if (port >= 0 ) {
    return port;
  }

  return false;
}

/**
 * Event listener for HTTP server "error" event.
 */
function onError(error) {
  if (error.syscall !== 'listen') {
    throw error;
  }

  const bind = typeof port === 'string'
    ? 'Pipe ' + port
    : 'Port ' + port;

  // handle specific listen errors with friendly messages
  switch (error.code) {
    case 'EACCES':
      console.error(bind + ' requires elevated privileges');
      process.exit(1);
      break;
    case 'EADDRINUSE':
      console.error(bind + ' is already in use');
      process.exit(1);
      break;
    default:
      throw error;
  }
}

/**
 * Event listener for HTTP server "listening" event.
 */
function onListening() {
  const addr = server.address();
  const bind = typeof addr === 'string'
    ? 'pipe ' + addr
    : 'port ' + addr.port;
  debug('Listening on ' + bind);
  console.log('> LEARNING_API listening on %s in %s', port, env);
}